High spatial resolution IR observations of young stellar objects - A possible disk surrounding HL Tauri

Grasdalen, G. L.; Strom, S. E.; Strom, K. M.; Capps, R. W.; Thompson, D. T.; Castelaz, M. W.

doi:10.1086/184333

Cited by 52 publications

(21 citation statements)

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“…Some very young stars show a Planckian radiation curve with an excess emission in the infrared part of the spectrum. This is reasonably ascribed to the presence of an extensive cool dusty disc around the star (Beck & Beckwith 1984; Grasdalen et al 1984; Strom et al 1985). Such observations are consistent with nebula‐based theories that require a dusty disc accompanying a newly formed star.…”

Section: Relevant Observationsmentioning

confidence: 94%

The formation of planetary systems

Oxley¹,

Woolfson²

2004

Monthly Notices of the Royal Astronomical Society

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In an embedded cluster, with high stellar densities, interactions can occur between stars and either newly formed diffuse protostars or high‐density regions produced by the collision of turbulent elements. It is shown by smoothed particle hydrodynamics (SPH) modelling that interactions can occur in which the complete protostar, or high‐density region, is extended into a filament and where planetary‐mass condensations in the filament are captured by the star. Other condensations can escape to form free‐floating planets. The SPH code used for this modelling contains a novel algorithm for radiation transfer that is applicable over all scales, all opacities and all optical depths. The captured protoplanets have orbits with initial semimajor axes mostly in the range 1000–2000 au, although occasionally larger or smaller, and with high eccentricities (∼0.7–0.9). Motion in a resisting medium, at least partially a by‐product of the interaction, gives a range of final orbits fully consistent with observations and suggests types of orbit that are, as yet, not amenable to detection. Estimates of the frequency of planetary companions for solar‐type stars comfortably satisfy the current 7 per cent observational estimate and even suggest that the frequency may turn out to be higher when planets of lower mass and larger orbits can be detected.

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Section: Relevant Observationsmentioning

confidence: 94%

The formation of planetary systems

Oxley¹,

Woolfson²

2004

Monthly Notices of the Royal Astronomical Society

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“…Moreover, recent high resolution infrared imaging of the T Tauri star HL Tau has provided strong evidence that the excess infrared emission around that object originates in a circumstellar disk (Grasdalen et al 1984).…”

Section: An Evolutionary Sequence?mentioning

confidence: 99%

Star Formation: From OB Associations to Protostars

Lada

1987

Symp. - Int. Astron. Union

143

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The study of star formation is a relatively young discipline of the field of astronomy. Up until the mid point of the twentieth century only a most rudimentary understanding of the subject was possible. This is because prior to that time there did not exist any substantive body of empirical data which could be used to critically test even the most basic hypotheses concerning stellar origins. However, as a result of impressive advances in observational technology and in our understanding of stellar evolution during the last forty years, the subject of star formation has developed into one of the most important branches of modern astrophysical research. A large body of observational data and a considerable literature pertaining to this subject now exist and a significant fraction of the international astronomical community devotes their efforts towards trying to comprehend the origins of stars and planets. Yet, despite these efforts we have yet to observationally identify, with any certainty, a single object in the process of stellar birth! Moreover, we have not yet produced a viable theory of star formation, one capable of being tested and refined by critical experiment. In many ways, stellar birth is as much a mystery today as it was forty years ago. However, there can be little doubt that during the last two decades truly revolutionary progress has been made in the quest to understand the star formation process in our galaxy. This apparent paradox in the state of our knowledge concerning stellar origins is resolved with the realization that the history of the study of star formation has been a history of the study of progressively earlier and earlier stages of stellar evolution. Indeed, it is in precisely this area of endeavor that we have learned so much.

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“…It possesses almost all the current signposts associated with circumstellar disks, including a wellcollimated jet along P. A. 51Њ (Mundt, Ray, & Bührke 1988;Mundt et al 1990), scattered light along the same direction, assumed to be the axis of the disk Grasdalen et al 1984;Hodapp 1984;Beckwith et al 1989;Monin et al 1989, hereafter MPRL), infrared and millimeterwave thermal continuum radiation (Beckwith et al 1986;Cohen, Emerson, & Beichman 1989;, and molecular line emission in flattened distributions with regular velocity patterns assumed to be dominated by the gravity of the star (Sargent & Beckwith 1987, 1991Hayashi, Ohashi, & Miyama 1993;Lay et al 1994). The disk is one of the most massive and easily observed of those in large samples of young stellar objects (Beckwith et al 1990, hereafter BSCG).…”

Section: Introductionmentioning

confidence: 99%

Vertical Disk Structure in HL Tauri

Beckwith

Birk

1995

The Astrophysical Journal

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New J, H, and KЈ images of HL Tau show that the position of the peak intensity shifts by 0"53 H 0"07 along P. A. 75Њ H 8Њ between 2.12 m (KЈ) and 1.25 m (J). There is a strong gradient in the color of the extended light around in the same direction. This direction is coincident with the axis of the optical emission jet and the axis of the circumstellar disk inferred from millimeter-wave maps. It is likely that the star itself is viewed through more than 30 mag of visual extinction and is only seen directly at wavelengths longer than about 1.6 m; the distribution of light at J is more diffuse, and the peak is probably the result of viewing an extended region of scattered light behind a gradient of extinction. The projected scale height of the extinction gradient is less than a few tens of AU along a direction nearly perpendicular to the disk, indicating that the extinction gradient is local to HL Tau, within a few hundred AU of the star. The distribution and color of the extended light suggest that it is scattered by an extended, conical nebula surrounding the star associated with the molecular infall observed in 13 CO.

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High spatial resolution IR observations of young stellar objects - A possible disk surrounding HL Tauri

Cited by 52 publications

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The formation of planetary systems

The formation of planetary systems

Star Formation: From OB Associations to Protostars

Vertical Disk Structure in HL Tauri

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